Dropout recloser

ABSTRACT

A dropout recloser is capable of in accordance with its operating programming after a predetermined number of fault interrupting operations, e.g., 1, 2, 3 or more but typically 3, to drop out of a cutout and hang freely in a hinge contact of the cutout providing sectionalization with an observable visible gap. The recloser includes fault interrupting and reclosing components, a drop out mechanism and a controller. The drop out mechanism may include a bi-stable actuator to affect fault interrupting operation and dropout operation. The device may include motion limiting structures. The recloser may have a number of operating modes or sequences.

CROSS-REFERENCE RELATED TO APPLICATIONS

This application is continuation of prior U.S. application Ser. No.16/866,656, filed May 5, 2020, which is continuation of prior U.S.application Ser. No. 14/399,534, filed Nov. 9, 2014, which is a nationalstage entry of International Application Number PCT/2013/039857, filedMay 7, 2013, which claims priority of U.S. Application No. 61/643,593,filed May 7, 2012, which are all hereby incorporated herein by referencein their entirety.

TECHNICAL FIELD

This patent relates to electric transmission and distribution systemfault detection, fault isolation and protection devices, sectionalizersand reclosers, and in particular, this patent relates to self-reclosing,dropout recloser devices and methods.

BACKGROUND

U.S. patent application Ser. No. 12/095,067, filed Jul. 16, 2008, thedisclosure of which is hereby incorporated herein by reference andcommonly assigned to the owner of this patent describes a faultinterrupting and reclosing device of a self-contained design. The deviceconveniently fits within conventional cutouts, provides fault detectionand fault interruption, reclosing/service restoration and dropoutsectionalizing lock out with a visible gap. A corresponding commercialproduct is the dropout recloser marketed and sold by S&C ElectricCompany of Chicago, Ill., United States of America under the trademarkTripSaver®, which has received broad acclaim being named a winner of the2008 R&D 100 Awards Competition and a winner of the 2007 ChicagoInnovation Awards Competition as well as having commercial success.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a dropout recloser according to hereindescribed embodiments electrically coupled within a cutout.

FIG. 2 is a side view of the dropout recloser shown in FIG. 1, in adropout position.

FIG. 3 is side perspective view of the dropout recloser shown in FIG. 1,the housing portion thereof being depicted in phantom to revealcomponents disposed therein.

FIG. 4 is a side perspective view of the dropout recloser shown in FIG.1 with the housing portion removed to reveal the internal components ofthe dropout recloser.

FIG. 5 is a side view of the dropout recloser shown in FIG. 1 with thehousing portion removed to reveal the internal components of the dropoutrecloser.

FIG. 6 is a view taken along lines 6-6 of FIG. 5 depicting a bottomhousing portion of the dropout recloser and a display device disposedtherein.

FIG. 7 is a side perspective view of a trunnion that may be used in thedropout recloser of FIG. 1.

FIG. 8 is an enlarged view of the trunnion shown in FIG. 7 disposedwithin a lower contact assembly of a cutout.

FIG. 9 is a side view of an actuator suitable for use in various devicesincluding a dropout recloser as depicted in FIG. 1.

FIG. 10 is a perspective view of the actuator depicted in FIG. 9.

FIG. 11 is a graphic illustration of the actuator depicted in FIG. 9 ina first position.

FIG. 12 is a graphic illustration of the actuator depicted in FIG. 9 ina second position different than the first position shown in FIG. 11.

FIG. 13 is a graphic illustration of a partial perspective view of theactuator depicted in FIG. 9.

FIG. 14 is a graphic illustration of a section view of the actuatordepicted in FIG. 9.

FIG. 15 is a graphic illustration of a section view of an alternateembodiment of the actuator depicted in FIG. 9.

FIG. 16 is a circuit to determine the position of an actuator such asthe actuator depicted in FIG. 9.

DETAILED DESCRIPTION

FIG. 1 depicts a dropout recloser 100 (referred to herein either as thedropout recloser 100 or the recloser 100) coupled within a cutout 102.The cutout 102 is of conventional construction as such as the Type XSCutout available from S&C Electric Company, Chicago, Ill., USA. Thecutout 102 includes a mounting 104, an insulator 106, first springbiased contact 108 and second hinge contact 110. The hinge contact 110includes a hinge portion 112 formed with a pivot receiving slot 114 withan integral retaining structure 116. The cutout 102 is depicted anddescribed to facilitate the following discussion of the structure andoperation of the dropout recloser 100.

The recloser 100 includes a housing 120 for the recloser 100. Thehousing 120 may be a unitary structure or an assembly of housingportions. As shown the housing 120 includes first and second portions.The recloser 100 includes a trunnion or terminal 122 including a pivot124. The trunnion 122 extends from a side portion as depicted in thedrawing of the housing 120. The recloser 100 also includes a post-likecontact or terminal 126 disposed at an upper portion as depicted in thedrawing of the housing 120. The hinge portion 112 and in particular thepivot receiving slot 114 receives the trunnion 122 and pivot 124 and thespring-biased contact 108 engages the contact 126 to secure the recloser100 in the cutout 102 and electrically couple the recloser 100 to thecutout 102.

The recloser 100 is a dropout recloser. A dropout recloser is capable ofin accordance with its operating programming after a predeterminednumber of fault interrupting operations, e.g., 1, 2, 3 or more buttypically 3, to drop out of the cutout 102 and hang freely in the hingecontact 110 providing sectionalization with an observable visible gap.As will be described, the recloser 100 includes fault interrupting andreclosing components, a drop out mechanism and a controller. The dropout mechanism coupled to the trunnion 122 allows translation and/orarticulation of the entire recloser 100 relative to the trunnion 122 inthe direction of arrow “A” in FIG. 1. This motion of the recloser 100releases the contact 126 from contact 108 freeing the recloser 100 torotate about pivot 124 in the hinge 112. FIG. 2 reflects the recloser100 after this action of releasing the recloser 100 from the cutout 102to a dropout position.

FIGS. 3-5 are illustrations of the operative components of the recloser100 internal to the housing 120. An advantage of the recloser 100 isthat in addition to the fault isolation/reclosing components, the dropout mechanism except for the portion of the trunnion 122 extendingoutwardly from the housing 120 are contained within the housing 120.Hence, the recloser 100 enjoys excellent weather resistance. A seal 132and seal garter 134 provide weather-tight sealing of the housing 120where the trunnion 122 extends through.

The contact 126 extends through a bushing 138 that is formed integrallywith a D-ring handle 140 and a bump stop 142 fitted with an insulatingbumper 144. Extending through the bushing 138 the contact 126 iselectrically coupled to a first side 150 of a vacuum interrupter 152secured within the housing 120 by threaded fasteners 154 engaging avacuum interrupter guide structure 155 with boss structures 156 formedwithin the housing 120. In this manner, the contact 126 is coupled to astationary contact (not depicted) of the vacuum interrupter 152. Aflexible contact assembly 160 electrically couples a moving contact (notdepicted) of the vacuum interrupter 152 and hence the contact 126internally within the housing 120 to a power supply and sensing assembly166 and via a terminal structure 162 (an intermediate flexible conductornot depicted) and from the assembly 166 via a conductor 168 to thetrunnion 122.

The moving contact of the vacuum interrupter 152 is coupled to anactuating rod 170 that extends within the housing 120 to an actuator172. A bias spring 176 engages the rod 170 and provides a bias force onthe rod 170. Described later, the actuator 172 may be a dual coil,bi-stable electro-magnetic solenoid.

A main frame plate 180 secured within the housing 120 provides afoundation for secure mounting of the power supply and sensor assembly166, the actuator 172, an electronic control module 186 and a dropoutassembly 190. A seal 193 ensures weather-tight sealing of the housing120 about the main frame plate. A magnetic control switch assembly 191is coupled to the control module 186 and is actuated via a selector 130.The control module further couples to a display 198 (FIG. 6).

The recloser 100 is designed to manage operating voltages up to orpotentially in excess of 34.5 kV, and fault currents up to orpotentially in excess of 4000 A. Suitable conducting and insulatingmaterials are therefore selected for its construction.

The dropout assembly 190 includes two mutually engaging operatingmembers 192 and 194 mounted on pivots 196 and 198. A solenoid actuator(not depicted) engages the member 192. The member 194 couples to anarticulating trunnion mount 200. The actuator drives members 192 and 194to release tabs 202. Under the weight of the recloser 100, the members192 and 194 rotate with the members 192 and 194 sliding along thesurfaces 204 and 206. The trunnion 122 articulates responsive to itscoupling to the member 194 and the recloser 100 translates relative tothe cutout 102 allowing for dropout for the recloser 100 from thecoupled position as depicted in FIG. 1 to the dropout configuration asdepicted in FIG. 2.

To control and limit the rotating motion of the reclosure 100 duringdropout, the pivots 124 may be formed with motion limiting structures210. The structures 210 may be radially extending arms formed integralwith the pivots 124.

Best seen in FIG. 8, the structures 210 engage the retaining structures116 of the hinge slots 114 limiting the arc through which the recloser100 moves during dropout. The recloser 100 does not stop abruptly uponengagement of the structures 210 with the structures 116; however, andthe recloser 100 advantageously utilizes its weight to provide slowrotation and provide damping. As the structures 210 engage thestructures 116 they lever the trunnion 122 in a motion translating thetrunnion 122 and hence the recloser 100 in the hinge slot 114. Thismotion is depicted in phantom in FIG. 8. Causing the recloser 100 tolift its own weight on dropout quickly dissipates the energy of dropout.

As an alternative to the radial arms 210 depicted in FIGS. 7 and 8, pinsmay be fitted to the trunnion 122 or other structures that ultimatelyengage the a portion of the hinge slot 114 to dissipate energy ofdropout and hence reduce rotational travel and oscillation.

FIG. 7 also illustrates the connecting boss structure 212 of thetrunnion 122 that extends into the housing 120 and allows coupling tothe dropout mechanism. A threaded fastener (FIGS. 3-5) may be used tosecure the trunnion 122. The trunnion 122 may also be formed with a hookloop 214 to facilitate placement of the recloser 100 in the cutout 102using a conventional hook stick.

The recloser 100 utilizes the actuator 172 to drive the moving contactof the vacuum interrupter 152 from a make position to a break positionand vice versa. This is accomplished via exertion of axial force to theconnecting rod 170. The actuator 172 may be a device having two stablestates corresponding with the contact make and contact break positionsof the vacuum interrupter 152, i.e., latching ability, while stillproviding sufficient driving force to break the contacts of the vacuuminterrupter 152 under fault current conditions and to make the contactsquickly.

Actuator

The actuator 300 illustrated in FIGS. 9-15 may be used in the recloser100. The actuator 300 is of the bi-stable-type operators, and embodiespole pieces that transmit flux to the operator from one or more flatmagnets. Flat magnets are easy to manufacture and magnetize. Theactuator 300 also stabilizes and locates the magnets and pole pieceswithin a molded cavity of a common coil bobbin without the need forglues or adhesives. Structures of bi-stable actuators and theory ofoperation are described in Appendix A.

As shown in the figures, actuator 300 includes two pole pieces 302 and304 concentrating two permanent magnets 306 and 308, for examplesuitable permanent magnets include NdFeB magnets, around anoperator/plunger 310. Two coils 312 and 316 (FIG. 9), for examplesuitable coils include 250T coils, mounted on a single bobbin 318 withina frame 320 toggle the plunger 310 between stable states. The frame maybe a simple structure of 4 plates of suitable metal or non-metallicstructural material. The actuator 300 latches at each end of its stroke(FIGS. 11 and 12) and provides forces to toggle from one end to theother as well as to drive a load. The coils 312 and 316 toggle lines offlux from the magnets 306 and 308 from one end of the plunger 310 to theother.

The coil bobbin 318 embodies a linear bearing surface to guide, supportand constrain the moving plunger 310 while preventing a frictionalinterface at the center magnetic pole face interface where it wouldotherwise form a friction brake preventing movement. Alternatively oradditionally a non-stick surface such as a Teflon® or other non-slipsurface may be used to allow proper operation of the actuator 300.

The pole pieces 302 and 304 have a generally square frustum cuboidconfiguration with a convex face surfaces 330 and 332 and square planarbase surfaces 334 and 336. The square planar base surfaces 334 and 336correspond generally in shape with the square planar face surfaces ofthe magnets 306 and 308. The square frustum cuboid configuration of thepole pieces 302 and 304 acts to concentrate magnetic flux of the magnets306 and 308 about the plunger 310. The pole pieces may be constructedfrom any suitable magnetic flux concentrating material. Suitablematerials will have high magnetic permeability and low power loss. Thesematerials include, for example, ferrous metals and their alloys inlaminate, homogenous, matrix or any other suitable form.

As is appreciated, the actuator 300 utilizes inexpensive flat magnets306 and 308 to avoid difficulties of using radially charged magnets andgains the freedom of choosing from a wider range of magnet area, lengthand pole face area than the existing direct magnet face allows.

Actuator 300 uses a fully encompassing center pole area 340 whichreduces losses incurred by other approaches. By surrounding a highpercentage of the periphery of the moving component, theoperator/plunger 310 the pole piece(s) 302 and 304 reduce the losses dueto leakage and avoid the limitations of area to plunger face ratios Amagnet area of (for instance) five square inches can be efficientlyapplied to three square inches of the moving part with whatever shapemay be desired for the transfer of the flux.

Virtually any number of pole pieces may be used. FIGS. 9-14 illustratestructures using two pole pieces, pole pieces 302 and 304. FIG. 15illustrates an actuator 400 that utilizes four pole pieces 402, 404, 406and 408 coupling magnets 410, 412, 414 and 416 acting on an operator418. The four pole pieces 402, 404, 406 and 408, magnets 410, 412, 414and 416 and operator 418 are retained within a bobbin 420 for coils (notdepicted).

Position Detection

The actuator 172 used in the recloser 100 and the actuator 300, aparticular embodiment of an actuator that may be used in the applicationprovided by the actuator 172, has two stable positions. In operation, itmay become necessary to determine the position of the actuator. Byextension, in the recloser 100, the position of the actuator 172corresponds to the make or break position of the moving contact of thevacuum interrupter 152. One solution is to provide a sensor that sensesactuator position. This solution adds cost and complexity. It would bepreferable to determine the position of the actuator without adding asensor or other device.

In the embodiments of the actuators described herein, and in connectionwith other similarly constructed actuators, two coils are used to drivethe actuator between its two stable positions. For example, in theactuator 172, two coils are used to drive the actuator between the makeand break contact vacuum interrupter 152 contact positions and in theactuator 300, two coils 312 and 316 are used to drive the actuatorbetween its two stable positions.

FIG. 16 provides a circuit schematic of a two coil, two positionbi-stable actuator. A tap 500 is provided between first coil 502 andsecond coil 504 (inherent resistance also being represented). A pulldown resistor is coupled at tap 500. Switch structures 506, 508, 510 and512 allow for selectively energizing coils 502 and 504 to operate theactuator. The switches 506, 508, 510 and 512 also allow for selectivelypulsing the coils 502 and 504 as described to determine position of anoperator of the actuator. Voltage sensing is provided at tap 500, andvoltage and current sensing is provided as applied to the actuator,i.e., the coils. Circuit capacitance is also represented in the figure.

To determine operator position, a short voltage pulse (or current pulse)is applied to the coils 502 and 504. The relative coil response showswhich coil has the open gap, and hence the position of the operator.

As depicted in FIG. 16, the two series connected coils 502 and 504 areof equal coil construction. A short pulse of coil power is applied andthe center tap between the coils is sensed for relative voltage. Thecoil with the higher voltage drop has the closed magnetic gap. Of coursethe coils may be of different design, e.g., different numbers of ortypes of windings. With such coils it is a matter of calibrating todetermine the indicative voltage drops.

One example of the ways to perform the position check is to apply thecoil power for ¼ millisecond while measuring the relative voltage at thecenter tap 500 between the series coils 502 and 504. The coil (502 or504) with the closed gap will have a voltage greater than ½ of theapplied voltage. The short time during which voltage or current isapplied to the coils 502 and 504 is below the minimum mechanicalresponse time to affect operation. The coil polarity may also be chosento drive the actuator into its existing position, i.e., close a closedactuator or open an open actuator. The existing actuator position may bebased on either the last measured position, or last open or closecommand. To virtually eliminate the possibility that the actuator willchange state, the pulse duration is to be a very short percentage of thepulse time required to release the actuator. For example, a ¼millisecond pulse could be used when the minimum pulse time needed toreduce the holding force to a release level is greater than 5milliseconds. For this example less than 5% of the release pulseduration.

In the recloser 100, a three wire connector 240 couples the actuator172, i.e., the two coils and the center tap, to the controller 186 foroperating the device. The controller 186 is programmed to provide thevarious operating sequences such as fault trip, reclose, fault trip,drop out; one trip to drop out; operations count, vacuum interrupterend-of-service-life determination, and the like. The various operatingmodes are selected by manipulation of the arm 130 and the magneticswitch 191. Additionally, device operating mode, status and the like maybe indicated on the display 198.

Hence, manipulation of the arm 130 may cause the controller 186 todisplay in scroll fashion various device information to the display ormanipulation of the arm 130 may allow selection of displayedinformation. Additional manipulation of the arm 130 may allow setting ormodification of device operating parameters. For example, the device maybe set to operate in standard reclose mode (1 or more reclose attemptsbefore sectionalizing), sectionalize mode (sectionalize on first faultindication), fault withstand mode, and the like.

A fault withstand mode may be invoked when the recloser 100 detectsfault current in excess of the interrupting rating capability of thedevice. In this situation, the recloser 100 may maintain its state,i.e., the device remains in a closed state until an indication thatother protective devices, e.g., an upstream breaker has operated. Upondetecting that an upstream device has operated, e.g., by detecting lossof voltage, to cause the recloser 100, to dropout during this interval.Alternatively, the device may be set to fault count, i.e., to determinethat a selectable/lettable number of excess fault current situationshave occurred and then to dropout during a next suitable open interval.Detection of fault current at or below the current interrupting ratingof the recloser 100 allows it to operate in accordance with its currentoperating settings.

We claim:
 1. A device for interrupting the flow of electricity in acircuit, the device being configured for mounting in a cutout coupled tothe circuit, including a first external electrical contact and a secondexternal electrical contact, the first and second external electricalcontacts being coupled to a vacuum interrupter disposed within anhousing of the device, the vacuum interrupter having a first contactmovable relative to a second contact for making or breaking anelectrical circuit between the first external electrical contact and thesecond external electrical contact and responsive to a force exertedupon the first contact by an actuator coupled to the first contact, thedevice having a trunnion for engaging a hinge portion of the cutout, thetrunnion formed with structures that engage the hinge portion upondropout of the device from the cutout to limit rotation of the devicewithin the hinge portion.
 2. The device of claim 1, wherein thestructures comprise arms to affect lifting of the device within thehinge portion to thereby use the weight of the device to slow itsrotation within the hinge.
 3. The device of claim 1, wherein thestructures comprise means for limiting dropout rotation of the deviceupon dropout of the device from the cutout.
 4. A device for interruptingthe flow of electricity in a circuit, the device being configured formounting in a cutout coupled to the circuit, including a first externalelectrical contact and a second external electrical contact, the firstand second external electrical contacts being coupled to a vacuuminterrupter disposed within an housing of the device, the vacuuminterrupter having a first contact movable relative to a second contactfor making or breaking an electrical circuit between the first externalelectrical contact and the second external electrical contact andresponsive to a force exerted upon the first contact by an actuatorcoupled to the first contact, the device having selectable operatingsequences, the operating sequences being selectable via a switchdisposed within the housing that is magnetically actuated by an armdisposed external of the housing.